1. Technical Field
This invention relates in general to handheld devices and more particularly, to audio systems for such devices.
2. Description of the Related Art
Many handheld devices, such as personal digital assistants (PDA), mobile telecommunications units and gaming units, use batteries to power their electronics. In most of these devices, one or more speakers are included to broadcast voices or digitally generated tones, such as musical notes.
In general, a power amplifier is used to drive the speakers in these devices. The batteries in these devices supply voltage directly to the power amplifier. As a result, the output of the power amplifier is dependent on the voltage supplied by the batteries. Because of this relationship, as the charge on the batteries begins to drop, the output of the power amplifier is affected. Notably, however, the signal input to the power amplifier, which has a much lower voltage level than that of the output of the power amplifier, is literally independent of the battery voltage swings.
Accordingly, when the battery voltage drops, the output signal from the power amplifier may be clipped. This clipping will produce low quality audio, and the user of the device may hear a distorted signal when it is broadcast from the speaker. Thus, there is a need for a system and method for maintaining the quality of audio generated by a device that outputs audio when the power supply of that device begins to deteriorate.